The Anatomy of the Rapid RH®

Concrete moisture measurement meets the new era with the Wagner Meters Rapid RH^® in situ relative humidity test method for measuring concrete slab moisture. Not only does it provide a fast, accurate and easy-to-use job site experience, but the Rapid RH also fully complies with the latest version of the ASTM standard, ASTM F2170: “Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.” The Rapid RH features the latest Touch-n-Sense™ technology and an innovative sleeve liner design for dependable relative humidity results.

The American Society for Testing and Materials (ASTM) established ASTM F2170 in 2002 to acknowledge the methodological integrity of relative humidity moisture testing of concrete slabs. ASTM F2170 was an industry addition to the historic use of anhydrous calcium chloride (CaCl) to measure moisture vapor emissions rate (MVER) in concrete, a method that was being called into question for its accuracy. The Rapid RH affords contractors a scientifically-proven, cost-effective and accurate means of strictly adhering to ASTM F2170.

The Method

The Rapid RH uses NIST-certified Smart Sensor probes and their Total Reader^® digital display to easily and accurately measure relative humidity inside test holes drilled into slabs and placed at 40% of the slab depth. Assessors place the Smart Sensors, with stackable extensions, if necessary, into the test hole. The extensions allow the flexibility to completely line test holes at various depths. This ensures that gradient moisture inside the test hole itself does not compromise Rapid RH results.

The patented Rapid RH design equilibrates, in most cases, to read the relative humidity to within three percent of the final reading (defined by ASTM F2170 at 24 hours) only one hour after being placed in the test hole. While full compliance still requires the 24-hour limit, the Rapid RH provides the information crucial for informed business decisions about scheduling, using alternate adhesive or using other flooring choices within one hour.

Once users activate the Rapid RH Total Reader, it promptly displays the relative humidity reading and holds it for one minute after being removed from the Smart Sensor. Even better, the user may want to download the free Rapid RH DataMaster™ app, which facilitates the wireless transfer of RH test data to one’s mobile device. By eliminating the need for manual recording and reporting of data, the DataMaster app saves time and provides complete data integrity.

The Surface Practice

The anhydrous CaCl test of moisture vapor emission rate (MVER) has limitations. Put simply, MVER measures only the moisture that evaporates from the surface of the slab. This means CaCl is a surface test only and does not assess the moisture condition deeper down. Once floor coverings are applied, concrete will equilibrate and evenly distribute moisture from the bottom to the top of the slab. But because moisture will be distributed unequally during the drying process, the final equilibrated rate may fall far outside the flooring application specifications and lead to moisture-related problems.

Concrete moisture meter products are also surface-based assessments. They may measure up to three-quarter-inch of slab depth. However, concrete moisture meter accuracy can be negatively affected by slab density due to variable chemical and aggregate composition. Contractors are advised to never make a final determination on concrete readiness for floor covering based on concrete moisture meter results.

The Advantages of Going Deeper

The Wagner Meters Rapid RH is the fastest, most cost-effective way to meet ASTM F2170: “Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.”

Rapid RH sensors are uniquely designed to hold a small air pocket above the concrete in confinement when they are installed inside the test hole. Small fins on the sensor barrel create a “crush seal” that starts the clock for acclimation or equilibration time of the test hole from the moment the sensor is inserted. Readings can be taken immediately after the 24-hour test hole acclimation time period stipulated by F2170. Other in situ concrete RH test methods require additional sensor acclimation time, per test hole, after the 24-hour test hole acclimation.

The Concrete Moisture Test Starter Kit+ with Rapid RH is an all-in-one carrying case with all necessary materials, including five Smart Sensors. For repeat users, Wagner Meters offers Smart Sensor replacement packs. Buyers can save even more on bulk packaging purchases.

The Rapid RH sets the industry standard for dependable, cost-effective measurement of concrete moisture.